JP2014027775A - Anomaly detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anomaly detection device that can detect a disconnection between each battery cell constituting an assembled battery and a circuit for monitoring each battery cell even if a breakdown voltage of a Zener diode is set low.SOLUTION: The anomaly detection device includes: a plurality of detection terminals C connected to connection parts of adjacent battery cells 10; Zener diodes 21 connected in parallel between opposite terminals of the battery cells 10, respectively; a plurality of short-circuiting circuits 22 having short-circuiting switches 222 for short-circuiting the detection terminals C connected to the opposite terminals of the battery cells 10, respectively; a monitoring circuit 23 for controlling each short-circuiting circuit and detecting a terminal voltage between every adjacent detection terminal C; and a control section 24b for determining whether or not there is a disconnection between the connection part of every adjacent battery cell 10 and the detection terminal C on the basis of a corrected voltage value obtained by removing a variation component variable in accordance with a cell voltage Vc of the battery cell 10 and a protection voltage Vz of the Zener diode 21 from a terminal voltage Vp available when the short-circuiting switch 222 is turned on.

Description

  The present invention relates to an abnormality detection device that detects an abnormality of a battery pack configured by connecting a plurality of battery cells in series.

  Conventionally, in an assembled battery configured by connecting a plurality of battery cells in series, abnormalities such as overcharge / discharge of each battery cell based on the voltage between each detection terminal connected to both terminals of each battery cell An anomaly detection device having a monitoring circuit for detecting is connected.

  This type of abnormality detection device is provided with a short circuit having a short-circuit switch for short-circuiting both terminals of each battery cell for each battery cell in order to suppress variations in voltage of each battery cell constituting the assembled battery. Then, the battery cell having a high voltage is discharged by operating the short circuit (turning on the short circuit switch).

  In addition, in the abnormality detection device, in addition to an abnormality such as overcharge / discharge of each battery cell, a device that detects a connection failure (disconnection) between both terminals of each battery cell and a detection terminal connected to the both terminals. It is known (see, for example, Patent Document 1).

  In addition, the conventional disconnection detection method is such that when the short circuit switch of the short circuit provided between the detection terminals of the battery cell is turned on, the voltage of the corresponding battery cell is higher than the normal operating voltage range of the battery cell. When the value is equal to or lower than the abnormality determination threshold value set to a low value, a method is employed in which it is determined that a disconnection has occurred between both terminals of each battery cell and the detection terminal.

Japanese Patent No. 3606031

  By the way, the present inventors are considering to install a Zener diode between both terminals of each battery cell in order to protect a circuit constituting the abnormality detection device from an overvoltage generated in the assembled battery. In this case, if the breakdown voltage (zener voltage) of the Zener diode is set high, a voltage exceeding the withstand voltage of the monitoring circuit may be applied to the monitoring circuit. Therefore, it is desirable to set the breakdown voltage low.

  FIG. 7 is a circuit diagram showing an example of the abnormality detection apparatus that the present inventors are examining. As shown in FIG. 7, each detection terminal Ci to Ci + 2 connected to both terminals of a pair of adjacent battery cells Ai and Ai + 1 in the assembled battery, functions as a monitoring circuit and a short circuit connected to each detection terminal Ci to Ci + 2 In the abnormality detection device including the short-circuit switches SWi, SWi + 1, etc., Zener diodes ZDi, ZDi + 1 are connected in parallel between both terminals of the battery cells Ai, Ai + 1.

  However, with such a configuration, there is a problem that the disconnection between both terminals of each battery cell and the detection terminal cannot be properly detected by the disconnection detection method of the prior art.

  Explaining this point, for example, when a disconnection occurs between the connection part of each battery cell Ai, Ai + 1 in FIG. 7 and the detection terminal Ci + 1, the short-circuit switch SWi + 1 corresponding to the battery cell Ai + 1 is turned on. The voltage for each battery cell Ai, Ai + 1 is applied to the Zener diode ZDi, and the Zener diode ZDi breaks down. As a result, a discharge current flows from the positive terminal of the battery cell Ai to the negative terminal of the Zener diode ZDi → the short-circuit switch SWi + 1 → the battery cell Ai + 1 (see the thick arrow in FIG. 7).

  At this time, if the breakdown voltage of the Zener diode ZDi is set low, the voltage at the detection terminal Ci + 1 becomes a value close to the operating voltage range of the battery cell at the normal time, and exceeds the abnormality determination threshold value.

  For example, the voltage value of each battery cell Ai, Ai + 1 is 4V (operating voltage range: 3-5V), the breakdown voltage of each zener diode ZDi, ZDi + 1 is set to 5.1V, and the disconnection determination threshold Vth is set to 0.1 It is assumed that In this case, when a disconnection occurs between the connection portion of each battery cell Ai, Ai + 1 and the detection terminal Ci + 1, when the short-circuit switch SWi + 1 corresponding to the battery cell Ai + 1 is turned on, the voltage at the detection terminal Ci + 1 is The value is close to the use voltage range of the cell Ai + 1 (for example, 2.9 V), and exceeds the abnormality determination threshold value (for example, 0.1 V).

  In this way, when a Zener diode is added between both terminals of each battery cell for the abnormality monitoring device, detection when the short-circuit switch is turned on according to the cell voltage of each battery cell and the breakdown voltage of the Zener diode. Since the inter-terminal voltage varies between the terminals, the conventional disconnection detection method cannot appropriately detect the disconnection between both terminals of each battery cell and the detection terminal.

  Note that setting the breakdown voltage of each Zener diode to a high value may reduce the voltage at the detection terminal relative to the operating voltage range of the battery cell during normal operation, but the protection of the monitoring circuit, etc. is insufficient. It can not be adopted because there is a risk of becoming.

  In view of the above points, the present invention provides an abnormality detection device capable of detecting a disconnection between each battery cell constituting a battery pack and a circuit monitoring each battery cell even if the breakdown voltage of the Zener diode is set low. The purpose is to provide.

  The present invention is directed to an abnormality detection device that detects an abnormality of an assembled battery (1) configured by connecting a plurality of battery cells (10) in series.

  In order to achieve the above object, according to the first aspect of the present invention, among the plurality of battery cells, the plurality of detection terminals (C) connected to the connection portions of the adjacent battery cells and both ends of each of the plurality of battery cells. A zener diode (21) connected in parallel between the terminals and holding the voltage between both terminals of the battery cell below a predetermined protection voltage, and a detection connected to both terminals of the battery cell among the plurality of detection terminals A plurality of short-circuit circuits (22) having a short-circuit switch (222) for short-circuiting the terminals, switch control means (23a) for controlling on / off of the short-circuit switches in the plurality of short-circuits, and both terminals of the battery cell From the inter-terminal voltage detection means (23b) for detecting the inter-terminal voltage between the detection terminals and the inter-terminal voltage when the short-circuit switch is turned on by the switch control means, the cell voltage of the battery cell, and Based on the voltage correction means (24a) that removes fluctuations that vary according to the protection voltage of the Zener diode, and the correction voltage value corrected by the voltage correction means, between the connection portion of the adjacent battery cell and the detection terminal Disconnection determination means (24b) for determining whether or not a disconnection has occurred. The Zener diode is composed of elements whose protection voltage is higher than the maximum value that can be taken when the battery cell is normal and lower than the sum of the maximum values that can be taken when the adjacent battery cell is normal, and the voltage correction means is adjacent The correction coefficient corresponding to the fluctuation is calculated from the cell voltage of each battery cell and the voltage value of the protection voltage, and the correction coefficient is removed from the voltage between the terminals when the short-circuit switch is turned on by the switch control means. It is a feature.

  According to this, the fluctuation due to the cell voltage of the adjacent battery cell and the protection voltage by the Zener diode (the breakdown voltage of the Zener diode) is removed from the voltage between the detection terminals when the short-circuit switch is turned on. Based on the removed value, it is determined whether or not there is a disconnection between the connection portion of each battery cell and the detection terminal. Therefore, even if the breakdown voltage of the Zener diode is set low, the assembled battery It is possible to detect a disconnection between each battery cell that constitutes and a circuit that monitors each battery cell.

  Moreover, in invention of Claim 3, among several battery cells, in parallel between the some detection terminal (C) connected to the connection part of an adjacent battery cell, and both terminals of several battery cell The zener diode (21) that is connected and holds the voltage between both terminals of the battery cell below a predetermined protection voltage and the detection terminals connected to both terminals of the battery cell among the plurality of detection terminals are short-circuited. A plurality of short-circuits (22) having a short-circuit switch (222), switch control means (23a) for controlling on / off of the short-circuit switches in the plurality of short-circuits, and a terminal between detection terminals connected to both terminals of the battery cell Based on the inter-terminal voltage detecting means (23b) for detecting the inter-voltage, the inter-terminal voltage when the short-circuit switch is turned on by the switch control means, and a predetermined disconnection judgment threshold, A disconnection determining means (24b) for determining whether or not a disconnection has occurred between the connection portion of the cell and the detection terminal, and a voltage between the terminals that varies depending on the cell voltage of the battery cell and the protection voltage of the Zener diode. Threshold setting means (24c) for setting a disconnection determination threshold based on the variation. The Zener diode is composed of elements whose protection voltage is higher than the maximum value that can be taken when the battery cell is normal and lower than the sum of the maximum values that can be taken when the adjacent battery cell is normal, and the threshold setting means is adjacent A correction coefficient corresponding to the variation is calculated from the cell voltage of each battery cell and the voltage value of the protection voltage, and a correction value obtained by correcting a predetermined reference threshold value with the correction coefficient is set as a disconnection determination threshold value. .

  According to this, on the basis of the disconnection determination threshold set according to the cell voltage of the adjacent battery cell and the variation due to the protection voltage by the Zener diode (the breakdown voltage of the Zener diode), the connection portion and the detection terminal of each battery cell Therefore, even if the breakdown voltage of the Zener diode is set low, each battery cell constituting the assembled battery and a circuit for monitoring each battery cell are determined. It becomes possible to detect disconnection between the two.

  In addition, the code | symbol in the parenthesis of each means described in this column and the claim shows an example of a correspondence relationship with the specific means described in the embodiment described later.

1 is an overall configuration diagram of a power supply system according to a first embodiment. It is a block diagram which shows the principal part of the abnormality monitoring apparatus which concerns on 1st Embodiment. It is a circuit diagram which shows the principal part of the abnormality detection apparatus for demonstrating the action | operation of the abnormality monitoring apparatus which concerns on 1st Embodiment. It is a flowchart which shows the flow of the control processing which the control part which concerns on 1st Embodiment performs. It is a whole block diagram of the power supply system which concerns on 2nd Embodiment. It is a flowchart which shows the flow of the control processing which the control part which concerns on 2nd Embodiment performs. It is a circuit diagram which shows an example of the abnormality detection apparatus which the present inventors are examining.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
First, a first embodiment will be described with reference to the drawings. In this embodiment, the abnormality detection device of the present invention is applied to a power supply system mounted on a hybrid vehicle or an electric vehicle. As shown in the overall configuration diagram of FIG. 1, the power supply system of this embodiment includes an assembled battery 1 and an abnormality detection device 2 as main components.

  The assembled battery 1 is a power source that mainly supplies a traveling electric motor (not shown) to power various electric loads mounted on the vehicle. The assembled battery 1 according to the present embodiment includes a plurality of battery cells 10 formed of secondary batteries such as lithium ion batteries connected in series, and a plurality of battery blocks B1 grouped for each predetermined number of battery cells 10 adjacent to each other. It is comprised as a serial connection body of -Bn.

  The abnormality detection device 2 is a device that detects various states such as a voltage of the assembled battery 1 to detect an abnormality of the assembled battery 1, and each battery cell of the assembled battery 1 via a detection line L for voltage detection or the like. 10 are connected to both terminals.

  The abnormality detection device 2 according to the present embodiment includes a plurality of detection terminals C, a plurality of Zener diodes 21, a plurality of short circuits 22, a plurality of monitoring circuits 23, a control unit 24, and an insulating unit 25.

  The detection terminal C is provided in each detection line L, and is connected to at least one of both terminals (positive electrode terminal and negative electrode terminal) of each battery cell 10. For example, the detection terminal C is the positive terminal of each battery cell 10 except for the positive terminal of the battery cell 10 having the highest potential in the assembled battery 1 and the negative terminal of the battery cell 10 having the lowest potential in the assembled battery 1. And connected to the negative terminal respectively.

  The Zener diode 21 is an element that is connected in parallel between both terminals of each battery cell 10 and holds the voltage between both terminals of the battery cell 10 below a predetermined protection voltage (breakdown voltage). It functions as an overvoltage protection element that protects the monitoring circuit 23 from an overvoltage that occurs in the circuit. Each zener diode 21 has a cathode connected to a detection line connected to a high potential side terminal of the battery cell 10 among a pair of detection lines connected to both terminals of the battery cell 10, and a low potential side terminal. The anode is connected to the connected detection line.

  Each Zener diode 21 is set to a breakdown voltage in consideration of the voltage of the battery cell 10 and the withstand voltage of the monitoring circuit 23. Specifically, in order to protect the monitoring circuit 23, the Zener diode 21 has a breakdown voltage higher than the maximum value (for example, 5 V) that can be taken when each battery cell 10 is normal, and when the adjacent battery cell 10 is normal. An element lower than the maximum value (for example, 10 V) that can be taken is selected. Note that the breakdown voltage of the Zener diode 21 is stored in advance in the storage unit of the control unit 24 as the voltage value Vz of the protection voltage.

  The short circuit 22 is a circuit that equalizes the voltage variation of each battery cell 10 by flowing a discharge current from the battery cell 10 having a higher voltage than the other battery cells 10 among the plurality of battery cells 10. In the present embodiment, a plurality of battery cells 10 are provided correspondingly.

  Here, FIG. 2 is a diagram showing one battery block Bi among the plurality of battery blocks B1 to Bn and the monitoring circuit 23 corresponding to the battery block Bi. As shown in FIG. 2, the short circuit 22 includes a series connection body in which a resistor 221 and a short circuit switch 222 are connected in series.

  In the short circuit 22, one end of the series connection body on the resistor 221 side is connected to the detection terminal C on the positive side of the corresponding battery cell 10, and the other end of the series connection body on the short circuit switch 222 side is the corresponding battery cell. 10 is connected to the detection terminal C on the negative electrode side. For example, the short circuit 22 corresponding to the highest potential side in the battery block Bi (i = 1, 2,...) Of the assembled battery 1 has one end on the resistor 221 side connected to the detection terminal C1, and the other side on the short circuit switch 222 side. Two ends are connected to the detection terminal C.

  The resistor 221 constituting the short circuit 22 is configured by a resistance element having a predetermined resistance value. Moreover, the short circuit switch 222 in each short circuit 22 short-circuits the detection terminals connected to both terminals of the battery cell 10, and is composed of a semiconductor switch that is controlled to be turned on and off in response to a signal from the monitoring circuit 23. When the short-circuit switch 222 is controlled to be turned on, a discharge current from the battery cell 10 flows.

  A plurality of monitoring circuits 23 are provided corresponding to each of the battery blocks B1 to Bn, and according to a control signal from the control unit 24 described later, detection of a voltage state and the like in the corresponding battery blocks B1 to Bn, a short circuit 22 is a circuit that controls the 22 short-circuit switches 222.

  The monitoring circuit 23 according to the present embodiment includes a switch control unit 23 a that controls on / off of the short-circuit switch 222 and a voltage detection unit 23 b that detects a voltage between the detection terminals C connected to both terminals of the battery cell 10. .

  The switch control unit 23 a is a switch control unit that controls on / off of the short-circuit switch 222 in accordance with a control signal from the control unit 24. The switch control unit 23a of the present embodiment is configured to be able to switch on and off the short-circuit switch 222 of each short circuit 22 in a predetermined order.

  The voltage detection unit 23 b is an inter-terminal voltage detection unit that detects a voltage between the detection terminals C connected to both terminals of the battery cell 10, and a signal indicating a voltage detection result via the insulating unit 25 is transmitted to the control unit 24. Is configured to output.

  When the short-circuit switch 222 is turned on, the voltage detection unit 23b detects the inter-terminal voltage between the pair of detection terminals C connected to both terminals of each battery cell 10 as the inter-terminal voltage Vp for disconnection determination. Is configured to do.

  In addition, when the short-circuit switch 222 is controlled to be off, the voltage detection unit 23b according to the present embodiment detects the inter-terminal voltage between the pair of detection terminals C connected to both terminals of each battery cell 10 as the cell voltage Vc. Is configured to do.

  For example, when detecting the cell voltage of the battery cell 10 having the highest potential in the battery block Bi of the assembled battery 1, each detection when the short-circuit switch 222 connected to the pair of detection terminals C1 and C2 is controlled to be turned off. The voltage between the terminals C1 and C2 is detected as a cell voltage.

  Returning to FIG. 1, the control unit 24 includes a microcomputer including a CPU, a ROM, a RAM, an EEPROM, and the like and peripheral devices thereof, and executes various processes according to a control program stored in a storage unit such as a ROM. It is configured.

  The control unit 24 of the present embodiment is connected to each monitoring circuit 23 via the insulating unit 25. The insulating unit 25 is a circuit that transmits a signal between the control unit 24 and each monitoring circuit 23 in a state in which the control unit 24 and each monitoring circuit 23 are insulated from each other. Thus, it is possible to output various control signals to each monitoring circuit 23 and obtain signals from each monitoring circuit 23.

  Further, the control unit 24 according to the present embodiment executes an equalization process for equalizing the cell voltage variation of each battery cell 10 based on the cell voltage of each battery cell 10 acquired from each monitoring circuit 23. It is configured.

  For example, in the equalization process, when the variation in the cell voltage of each battery cell 10 acquired from each monitoring circuit 23 increases, the battery cell 10 that becomes a high voltage among the battery cells 10 is determined as a discharge target, The discharge time of the battery cell 10 is calculated. And the control part 24 outputs the control signal which shows the discharge instruction | indication of the battery cell 10 used as discharge object, and discharge time with respect to the monitoring circuit 23. FIG. Thereby, equalization of each battery cell 10 is implement | achieved because the monitoring circuit 23 turns ON the short circuit switch 222 of the short circuit 22 corresponding to the battery cell 10 used as discharge object for discharge time.

  In addition, the control unit 24 of the present embodiment is configured such that between the detection terminals C connected to both terminals of each battery cell 10 when the switch control unit 23a of the monitoring circuit 23 controls the short circuit switch 222 to be on. Disconnection between the connection part of the adjacent battery cell 10 and the detection terminal C based on the voltage correction process for correcting the voltage (inter-terminal voltage Vp for disconnection determination) and the voltage correction value corrected by the voltage correction process. It is configured to execute a disconnection determination process for determining whether or not an error has occurred.

  In the voltage correction process, the voltage between the detection terminals C connected to both terminals of each battery cell 10 when the switch control unit 23a controls on / off of the short-circuit switch 222 (inter-terminal voltage Vp for disconnection determination, And the cell voltage Vc) are obtained from the monitoring circuit 23.

  And the value which remove | eliminated the fluctuation part which fluctuates according to the cell voltage Vc of the adjacent battery cell 10 and the protection voltage of the Zener diode 21 from the voltage Vp between terminals for disconnection determination is calculated as a voltage correction value.

  More specifically, a correction coefficient α corresponding to the variation is calculated from the cell voltage Vc of each adjacent battery cell 10 and the voltage value Vz of the protection voltage of the Zener diode 21, and the correction coefficient α is the inter-terminal voltage for disconnection determination. The value removed from Vp is calculated as a voltage correction value (= Vp−α).

  Here, in the present embodiment, a subtraction value obtained by subtracting the voltage value Vz of the protection voltage of the Zener diode 21 from the total value of the cell voltages Vc of the adjacent battery cells 10 is calculated as the correction coefficient α. For example, when the total value of the cell voltages Vc of the adjacent battery cells 10 is 8 V and the voltage value Vz of the protection voltage of the Zener diode 21 is 5.1 V, the correction coefficient α is 2.9. The correction coefficient α and the voltage correction value are different for each detection terminal that detects the inter-terminal voltage Vp, and thus are calculated for each detection terminal.

  In the disconnection detection process, when the correction voltage value corrected in the voltage correction process is equal to or lower than the disconnection determination threshold value Vth set in advance to a value lower than the operating voltage range when the battery cell 10 is normal, It is determined that a disconnection has occurred between the connection portion of the battery cell 10 to be detected and the detection terminal C.

  The disconnection determination threshold value Vth is set to a value obtained by subtracting the maximum value Vcmax of the operating voltage range when the battery cell 10 is normal from the voltage value Vz of the protection voltage of the Zener diode 21. For example, when the maximum value of the working voltage range when the battery cell 10 is normal is 5 V and the voltage value Vz of the protection voltage of the Zener diode 21 is 5.1 V, the disconnection determination threshold Vth is set to 0.1.

  Here, in the circuit shown in FIG. 3, a case where a disconnection occurs between the connection portion of each battery cell Ai, Ai + 1 and the detection terminal Ci + 1 will be described. Note that the voltage values of the adjacent battery cells Ai, Ai + 1, Ai + 2 shown in FIG. It is assumed that the determination threshold Vth is set to 0.1.

  In this case, first, when the short-circuit switch SWi + 2 corresponding to the battery cell Ai + 2 is turned on, the inter-terminal voltage Vp at the detection terminal Ci + 2 becomes the same voltage value (about 4.0 V) as the voltage across the battery cell Ai + 2. The correction coefficient α is 2.9 because the sum of the cell voltages of the adjacent battery cells Ai + 1 and Ai + 2 is 8V and the breakdown voltage of the Zener diode ZDi is 5.1V.

  For this reason, the voltage correction value obtained by removing the correction coefficient α from the inter-terminal voltage Vp is approximately 1.1, which is a value equal to or higher than the disconnection determination threshold value Vth (0.1). Therefore, it can be detected that no disconnection occurs between the connection portion of each battery cell Ai + 1, Ai + 2 and the detection terminal Ci + 2.

  Subsequently, when the short-circuit switch SWi + 1 corresponding to the battery cell Ai + 1 is turned on, the inter-terminal voltage Vp at the detection terminal Ci + 1 becomes a value close to the use voltage range of the battery cell Ai + 1 (about 2.9 V). The correction coefficient α is 2.9 because the sum of the cell voltages of the adjacent battery cells Ai and Ai + 1 is 8V and the breakdown voltage of the Zener diode ZDi is 5.1V.

  For this reason, the voltage correction value obtained by removing the correction coefficient α from the inter-terminal voltage Vp is substantially zero, and is lower than 0.1 which is the disconnection determination threshold value Vth. Therefore, it is possible to detect that a disconnection has occurred between the connection portion of each battery cell Ai, Ai + 1 and the detection terminal Ci + 1.

  The configuration (software and hardware) for executing the voltage correction processing in the control unit 24 of the present embodiment constitutes the voltage correction means 24a, and the configuration (software and hardware) for executing the disconnection detection processing is disconnection determination means 24b. Is configured.

  Next, a flow of a series of control processes in the voltage correction process, the disconnection detection process, and the like executed by the control unit 24 according to the present embodiment will be described with reference to the flowchart of FIG. Note that the control routine shown in FIG. 4 is executed by the control unit 24 in accordance with a control signal from the host system while the vehicle is parked or stopped.

  First, a control signal instructing to turn on the short circuit switch 222 of the short circuit 22 corresponding to each battery cell 10 is output to each monitoring circuit 23 (S100). Thereby, each monitoring circuit 23 turns on the short-circuit switch 222 of the short-circuit 22 in a predetermined order, and detects the inter-terminal voltage Vp when the short-circuit switch 222 is turned on.

  Then, each terminal voltage Vp when the short-circuit switch 222 is controlled to be on is acquired from each monitoring circuit 23 (S110), and the acquired each terminal voltage Vp is stored in a storage means such as a RAM.

  Subsequently, a control signal instructing to turn off the short circuit switch 222 of the short circuit 22 corresponding to each battery cell 10 is output to each monitoring circuit 23 (S120). Thereby, each monitoring circuit 23 turns off the short circuit switch 222 of the short circuit 22 in a predetermined order, and detects the voltage between the terminals when the short circuit switch 222 is turned off as the cell voltage Vc of each battery cell 10.

  Then, the cell voltage Vc of each battery cell when the short-circuit switch 222 is controlled to be off is acquired from each monitoring circuit 23 (S130), and each acquired cell voltage Vc is stored in a storage unit such as a RAM.

  Subsequently, the correction coefficient α is calculated from the cell voltage Vc acquired in step S130 (the cell voltage Vc of each adjacent battery cell 10) and the voltage value Vz of the protection voltage of the Zener diode 21 (S140). Specifically, a subtraction value obtained by subtracting the voltage value Vz of the protection voltage of the Zener diode 21 from the total value of the cell voltages Vc of the adjacent battery cells 10 is calculated as the correction coefficient α.

  Subsequently, a voltage correction value is calculated by subtracting the correction coefficient α calculated in step S140 from the inter-terminal voltage Vp acquired in step S110, and the voltage correction value falls below a preset disconnection determination threshold Vth. It is determined whether or not (S150).

  As a result, when it is determined that the voltage correction value (= Vp−α) is not lower than the disconnection determination threshold value Vth (S150: NO), the connection between the connection portion of the adjacent battery cell 10 and the detection terminal C is determined. Is detected (S160), and the control process is terminated.

  On the other hand, when it is determined that the voltage correction value (= Vp−α) is lower than the disconnection determination threshold Vth (S150: YES), between the connection portion of the adjacent battery cell 10 and the detection terminal C. The disconnection is detected (S170), and the control process is terminated. In this case, the control unit 24 outputs to the host system that a disconnection has occurred between the connection part of the adjacent battery cell 10 and the detection terminal C.

  In the present embodiment described above, the cell voltage of each battery cell 10 included in the inter-terminal voltage Vp between the detection terminals C when the short circuit switch 222 of the short circuit 22 is turned on, and the protection voltage (the Zener diode) by the Zener diode 21. It is configured to determine whether or not a disconnection has occurred between the connection portion of each battery cell 10 and the detection terminal C based on the corrected voltage value from which the fluctuation due to the breakdown voltage 21) is removed.

  For this reason, even if the voltage value Vz of the protection voltage by the Zener diode 21 is set low, it is possible to detect a disconnection between each battery cell 10 constituting the assembled battery 1 and a circuit that monitors each battery cell. Become.

(Second Embodiment)
Next, a second embodiment will be described. In the present embodiment, an example will be described in which the disconnection determination threshold is set based on the variation of the inter-terminal voltage Vp that varies according to the cell voltage of the battery cell 10 and the protection voltage (breakdown voltage) of the Zener diode 21.

  The control unit 24 of the present embodiment is configured to execute the disconnection determination process using the threshold setting process for setting the disconnection determination threshold and the disconnection determination threshold set in the threshold setting process.

  In the threshold setting process, the voltage between the detection terminals C connected to both terminals of each battery cell 10 when the switch control unit 23a controls on / off of the short-circuit switch 222 (inter-terminal voltage Vp for disconnection determination, And the cell voltage Vc) are obtained from the monitoring circuit 23.

  Then, with respect to a preset reference threshold value Vth (for example, a range of 0 to 0.5), the inter-terminal voltage Vp that fluctuates according to the cell voltage Vc of the adjacent battery cell 10 and the protection voltage of the Zener diode 21. A value obtained by adding fluctuations is set as a disconnection detection threshold.

  More specifically, the correction coefficient α corresponding to the variation is calculated from the cell voltage Vc of each adjacent battery cell 10 and the voltage value Vz of the protection voltage of the Zener diode 21, and the value removed from the reference threshold Vth is the disconnection determination threshold. Calculate as (= Vth + α). In the present embodiment, a subtraction value obtained by subtracting the voltage value Vz of the protection voltage of the Zener diode 21 from the total value of the cell voltages Vc of the adjacent battery cells 10 is calculated as the correction coefficient α.

  In the disconnection detection process, when the voltage Vp between terminals for disconnection determination is equal to or lower than the disconnection determination threshold (= Vth + α) set in the threshold setting process, the connection portion and the detection terminal of the adjacent battery cell 10 are detected. It is determined that a disconnection has occurred with C.

  As shown in FIG. 5, the configuration (software and hardware) for executing the threshold setting process in the control unit 24 of the present embodiment constitutes the threshold setting means 24c.

  Next, a flow of a series of control processing in threshold setting processing, disconnection detection processing, and the like executed by the control unit 24 according to the present embodiment will be described with reference to the flowchart of FIG. Note that the control routine shown in FIG. 6 is executed by the control unit 24 in accordance with a control signal from the host system while the vehicle is parked or stopped.

  First, a control signal instructing to turn on the short circuit switch 222 of the short circuit 22 corresponding to each battery cell 10 is output to each monitoring circuit 23 (S100), and each terminal voltage when the short circuit switch 222 is controlled to be on. Vp is acquired from each monitoring circuit 23 (S110).

  Subsequently, a control signal instructing to turn off the short circuit switch 222 of the short circuit 22 corresponding to each battery cell 10 is output to each monitoring circuit 23 (S120), and each battery cell when the short circuit switch 222 is controlled to be turned off. Cell voltage Vc is acquired from each monitoring circuit 23 (S130).

  Subsequently, the correction coefficient α is calculated from the cell voltage Vc acquired in step S130 (the cell voltage Vc of each adjacent battery cell 10) and the voltage value Vz of the protection voltage of the Zener diode 21 (S140). Specifically, a subtraction value obtained by subtracting the voltage value Vz of the protection voltage of the Zener diode 21 from the total value of the cell voltages Vc of the adjacent battery cells 10 is calculated as the correction coefficient α.

  Subsequently, a value obtained by adding the correction coefficient α calculated in step S140 to a predetermined reference threshold value Vth is set as a disconnection determination threshold value (= Vth + α), and each inter-terminal voltage Vp acquired in step S110 is determined as a disconnection determination. It is determined whether it is below the threshold value (S180).

  As a result, when it is determined that the voltage Vp between the terminals does not fall below the disconnection determination threshold (S180: NO), a disconnection has occurred between the connection portion of the adjacent battery cell 10 and the detection terminal C. It is detected that there is not (S160), and the control process is terminated.

  On the other hand, when it is determined that the voltage Vp between the terminals is lower than the disconnection determination threshold (S180: YES), a disconnection occurs between the connection portion of the adjacent battery cell 10 and the detection terminal C. Is detected (S170), and the control process is terminated. In this case, the control unit 24 outputs to the host system that a disconnection has occurred between the connection part of the adjacent battery cell 10 and the detection terminal C.

  According to the present embodiment described above, each battery cell 10 and each battery cell constituting the assembled battery 1 are connected to each other even when the voltage value Vz of the protection voltage by the Zener diode 21 is set low as in the first embodiment. It is possible to detect a disconnection with a circuit to be monitored.

(Other embodiments)
The embodiment of the present invention has been described above, but the present invention is not limited to this, and can be appropriately changed without departing from the scope described in each claim. For example, various modifications are possible as follows.

  (1) In each of the above-described embodiments, the example in which the voltage between the terminals when the short-circuit switch 222 is controlled to be turned off is detected as the cell voltage Vc of the battery cell 10 is described. A circuit for detecting the voltage between both terminals in each battery cell 10 when the power is controlled to be turned off may be added, and the cell voltage Vc may be detected by the circuit.

  (2) In each of the above-described embodiments, an example in which the subtraction value obtained by subtracting the breakdown voltage (voltage value of the protection voltage) of the Zener diode 21 from the sum of the cell voltages Vc of the adjacent battery cells 10 is calculated as the correction coefficient α. However, the present invention is not limited to this. For example, a control map that defines the correlation between the sum of cell voltages Vc of adjacent battery cells 10, the breakdown voltage (voltage value of the protection voltage) Vz of the Zener diode 21, and the correction coefficient α is stored in the storage unit. By referring to the control map, the correction coefficient α may be calculated from the sum of the cell voltages Vc of the adjacent battery cells 10 and the voltage value Vz of the protection voltage by the Zener diode 21.

  (3) In each of the above-described embodiments, the example in which the abnormality detection device of the present invention is applied to the assembled battery 1 mounted on the vehicle has been described. However, the embodiment may be applied to the assembled battery 1 used other than the vehicle.

DESCRIPTION OF SYMBOLS 1 Battery assembly 10 Battery cell 21 Zener diode 22 Short circuit 222 Short circuit switch 23a Switch control part (switch control means)
23b Voltage detection unit (terminal voltage detection means)
24a Voltage correction means 24b Disconnection determination means

Claims (5)

In the abnormality detection device for the assembled battery (1) configured by connecting a plurality of battery cells (10) in series,
Among the plurality of battery cells, a plurality of detection terminals (C) connected to connecting portions of adjacent battery cells,
A Zener diode (21) connected in parallel between both terminals of each of the plurality of battery cells, and holding a voltage between both terminals of the battery cell below a predetermined protection voltage;
Among the plurality of detection terminals, a plurality of short circuits (22) having a short circuit switch (222) for short-circuiting the detection terminals connected to both terminals of the battery cell;
Switch control means (23a) for controlling on / off of the short-circuit switch in the plurality of short-circuits;
An inter-terminal voltage detection means (23b) for detecting an inter-terminal voltage between the detection terminals connected to both terminals of the battery cell;
Voltage correction means for removing fluctuations varying according to the cell voltage of the battery cell and the protection voltage of the Zener diode from the voltage between the terminals when the short-circuit switch is turned on by the switch control means ( 24a)
Disconnection determination means (24b) for determining whether or not a disconnection has occurred between the connection portion of the adjacent battery cell and the detection terminal, based on the correction voltage value corrected by the voltage correction means, With
The Zener diode is composed of an element whose protection voltage is higher than a maximum value that can be taken when the battery cell is normal, and lower than a maximum value that can be taken when the adjacent battery cell is normal,
The voltage correction means calculates a correction coefficient corresponding to the variation from the cell voltage of each of the adjacent battery cells and the voltage value of the protection voltage, and the correction coefficient is calculated by the switch control means. An abnormality detection device, wherein the abnormality detection device removes the voltage between the terminals when controlled to ON.   2. The abnormality detection according to claim 1, wherein the voltage correction unit calculates a subtraction value obtained by subtracting a voltage value of the protection voltage from a sum value of cell voltages of the adjacent battery cells as the correction coefficient. apparatus. In the abnormality detection device for the assembled battery (1) configured by connecting a plurality of battery cells (10) in series,
Among the plurality of battery cells, a plurality of detection terminals (C) connected to connecting portions of adjacent battery cells,
A Zener diode (21) connected in parallel between both terminals of each of the plurality of battery cells, and holding a voltage between both terminals of the battery cell below a predetermined protection voltage;
Among the plurality of detection terminals, a plurality of short circuits (22) having a short circuit switch (222) for short-circuiting the detection terminals connected to both terminals of the battery cell;
Switch control means (23a) for controlling on / off of the short-circuit switch in the plurality of short-circuits;
An inter-terminal voltage detection means (23b) for detecting an inter-terminal voltage between the detection terminals connected to both terminals of the battery cell;
Based on the voltage between the terminals when the short-circuit switch is turned on by the switch control means, and a predetermined disconnection determination threshold, a disconnection is generated between the connection portion of the adjacent battery cell and the detection terminal. Disconnection determining means (24b) for determining whether or not it has occurred;
Threshold setting means (24c) for setting the disconnection determination threshold based on the variation of the inter-terminal voltage that varies according to the cell voltage of the battery cell and the protection voltage of the Zener diode,
The Zener diode is composed of an element whose protection voltage is higher than a maximum value that can be taken when the battery cell is normal, and lower than a maximum value that can be taken when the adjacent battery cell is normal,
The threshold value setting means calculates a correction coefficient corresponding to the variation from the cell voltage of each of the adjacent battery cells and the voltage value of the protection voltage, and a correction value obtained by correcting a predetermined reference threshold value with the correction coefficient Is set as the disconnection determination threshold value.   4. The abnormality detection according to claim 3, wherein the threshold value setting unit calculates a subtraction value obtained by subtracting a voltage value of the protection voltage from a sum value of cell voltages of the adjacent battery cells as the correction coefficient. 5. apparatus.   5. The inter-terminal voltage detection means detects the inter-terminal voltage when the short-circuit switch is controlled to be turned off by the switch control means as a cell voltage of the battery cell. The abnormality detection apparatus as described in any one.

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